Answer: D
Explanation:
A mole corresponds to the mass of a substance that contains 6.023 x 1023 particles of the substance. The mole is the SI unit for the amount of a substance. Its symbol is mol. By definition: 1 mol of carbon-12 has a mass of 12 grams and contains 6.022140857 x 1023 of carbon atoms (to 10 significant figures)
Moles are the base unit or the smallest chemical entities that are present in the molecule, atom, or compound.
The one mole of a substance is equal to the amount of substance present in the Avogadro's number of particles of the substance.
Moles can be defined as:
Moles are the exactly [tex]6.02214\times 10^{23}[/tex] elementary entities present in the atoms, molecules, ions, or an electron. The value of given by the scientist Amedeo Avogadro, who is noted for the discovery of Avogadro's law and Avogadro's constant.
Thus, the correct answer is Option D.
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2
How
12.6
Sn + 2 HF - Snf a + H₂
many moles of tin (11) Fluoride will be produced
grams of hydrogen fluoride react?
if
Answer:
12.6 gram of HF will produced 0.315 moles of SnF₂
Explanation:
Given data:
Mass of HF = 12.6 g
Moles of Tin fluoride produced = ?
Solution:
Chemical equation:
Sn + 2HF → SnF₂ + H₂
Number of moles of HF:
Number of moles = mass/ molar mass
Number of moles = 12.6 g/20.01 g/mol
Number of moles = 0.63 mol
Now we will compare the moles of HF with SnF₂.
HF : SnF₂
2 : 1
0.63 : 1/2×0.63 = 0.315 mol
So 12.6 gram of HF will produced 0.315 moles of SnF₂.
How many grams of water are produced from the reaction of 1.26 mol of oxygen according to this equation?
2h2(g)+o2(g)=2h2o(g)
Answer:
45.4 g
Explanation:
Data given:
mole of oxygen = 1.26 mol
mass of water = ?
Reaction Given:
2H₂ (g) + O₂(g) --------> 2H₂O (g)
Solution:
To solve this problem we look for mole mole ratio oxygen to water we look for the chemical reaction
2H₂ (g) + O₂(g) ----------> 2H₂O (g)
1 mole 2 mol
So,
It is clear from the reaction that 1 mole oxygen gives 2 mole water then how many mole of water will produce by 1.26 moles of oxygen.
So apply unity formula
2 moles H₂O ≅ 1 mole O₂
X moles H₂O ≅ 1.26 mole O₂
Do cross multiplication
X moles H₂O = 2 mol x 1.26 mole / 1 mole
X moles H₂O ≅ 2.52 mol
So,
1.26 mole of oxygen produce 2.52 mole of water.
Now convert moles of water to mass
Formula will be used
mass in grams = no. of moles x molar mass
molar mass of water (H₂O)
molar mass of H₂O = 2(1) + 16
molar mass of H₂O = 2 + 16 = 18 g/mol
put value in above equation:
mass in grams = 2.52 mole x 18 g/mol
mass in grams = 45.4 g
So,
1.26 moles oxygen produce 45.4 g water
Is testing for fingerprints on a door a physical or chemical change
Answer:
Dusting for fingerprints makes use of the physical property of stickiness. Skin oils absorb the fingerprint dust, which is then collected on a sticky tape.
Dusting for fingerprints makes advantage of stickiness as a physical change. Skin oils adsorb the dust from fingerprints.
What is physical change ?Physical modifications are those that modify a chemical substance's shape but not its chemical content. Physical changes are normally unable to divide compounds into chemical elements or simpler compounds, although they can be utilized to separate mixtures into their components.
A physical change happens when a substance's physical characteristics change without undergoing chemical composition. Melting, changes in size, volume, color, and crystal shape are examples of common physical changes.
Thus, the dusting for fingerprints makes advantage of stickiness as a physical change. Skin oils adsorb the dust from fingerprints.
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How do you balance a chemical reaction?
Answer:
write down the number of atoms in each element, which is listed in the subscript next to each atom. Then, add coefficients to the atoms on each side of the equation to balance them with the same atoms on the other side.
Explanation:
Final answer:
To balance a chemical equation, write the correct formulas, count the atoms of each element, adjust coefficients to balance the atoms, use polyatomic ions as units, eliminate fractional coefficients for whole numbers, and check that all elements are balanced.
Explanation:
To balance a chemical reaction, one must ensure that the number of atoms for each element is equal on both sides of the equation. This is key to upholding the law of conservation of mass. The following steps are a simplified guide:
Write the skeleton equation with the correct formulas for reactants and products.
Count the number of atoms of each element in the reactants and in the products.
If the equation is not balanced, adjust the coefficients before the formulas, not the subscripts within them, to balance the atoms of each element.
Balance polyatomic ions as a unit if they appear unchanged on both sides of the equation.
Use fractional coefficients if necessary, and then multiply the entire equation to eliminate fractions and have whole number coefficients.
Perform a final check to ensure that all elements are balanced.
Throughout this process, one may use a trial-and-error approach to fine-tune the balancing, adjusting coefficients as needed until the number of atoms for each element is the same on both sides of the equation.
What is the mass of 5.43x1045 molecules of Beo
Answer:
2.255 x 10²³ g
Explanation:
Data Given:
no. of molecules of BeO = 5.43 x 10⁴⁵ molecules
mass of BeO = ?
Solution:
first we will find no. of moles
Formula used
no. of moles = no. of molecules / Avogadro's number
Where
Avogadro's number = 6.022 x 10²³
Put values in above equation
no. of moles = 5.43 x 10⁴⁵ molecules / 6.022 x 10²³ (molecules/mol)
no. of moles = 9.02 x 10²¹ mol
So,
There are 9.02 x 10²¹ moles of BeO of 5.43x10⁴⁵
Now we will find the mass
For this formula will be used
No. of moles = Mass in grams/ molar mass
Rearrange the above equation
mass in grams = no. of moles x molar mass . . . . . (1)
molar mass of BeO = 9 + 16 = 25 g/mol
Put values in equation 1
mass in grams = 9.02 x 10²¹ moles x 25 g/mol
mass in grams = 2.255 x 10²³ g
So,
Mass of 5.43 x 10⁴⁵ molecules of BeO = 2.255 x 10²³ g
The mass of 5.43x10^45 molecules of BeO can be calculated using the atomic masses provided in Appendix A.
Explanation:The mass of 5.43x10^45 molecules of BeO can be calculated using the atomic masses provided in Appendix A. The atomic mass of BeO is given by the formula BE = {[2m(^1H) + 2mn] - m(ª X)}c². We can substitute the atomic masses of ^1H (1.007825 u) and mn (1.008665 u) into the formula to calculate the binding energy (BE). By rearranging the formula, we can solve for the mass of 5.43x10^45 molecules of BeO.
in which atmosphere layer does 80% of the gas in the atmosphere reside
Answer:troposphere
Explanation:The troposphere is the layer that holds 80 percent of the total gas in the atmosphere.
Which of the following most likely happens when astronauts go to space?
1. Their heart rate speeds up because the blood vessels have less blood to circulate.
2. Their heart rate speeds up because the blood vessels have more blood to circulate.
3. The blood vessels in their neck caves in because the heart pumps less blood per beat.
4. The blood vessels in their neck bulges out because the heart pumps more blood per beat.
Answer:
4. The blood vessels in their neck bulge out.
Explanation:
This option is closest to being correct.
On Earth, the force of gravity pulls blood to the lower body. In space, the force of gravity is cancelled, so the blood spreads out evenly.
More blood in the upper body leads to increased blood pressure there, so the blood vessels in the neck bulge out.
The heart does not pump more blood per beat. Instead, it becomes lazy because it does not have to do as much work pumping blood back from the legs against the force of gravity.
A and B are wrong. You don't gain or lose blood simply by going into space.
C is wrong. The blood vessels in the neck bulge out.
The blood vessels in their neck bulge out because the heart pumps more blood per beat most likely happens when astronauts go to space.
Does the universe affect blood flow?In microgravity, the heart transforms from an elliptical shape (like a balloon filled with water) to a round sphere (a balloon filled with air), and the universe causes atrophy of the muscles that work on Earth and blood vessels. Shrinks. Nor can it control blood flow.
There are completely different results in the universe. There is no gravity that draws blood into the lower body. Instead, blood flows into the chest and head, the astronaut's face swells, and the blood vessels in the neck swell. And appearance isn't the only ugly side effect.
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What is the mass of 5 miles in ba3n2
Answer:
2200 g
Explanation:
Data Given:
no. of moles of Ba₃N₂ = 5 moles
mass of Ba₃N₂ = ?
Solution:
Formula used
no. of moles = mass in grams / molar mass
To find mass rearrange the above equation:
mass in grams = no. of moles x molar mass. . . . . . (1)
molar mass of Ba₃N₂
molar mass of Ba₃N₂ = 3(137.3) + 2(14)
molar mass of Ba₃N₂ = 412 + 28
molar mass of Ba₃N₂ = 440 g/mol
Put values in equation 1
mass in grams = 5 moles x 440 g/mol
mass in grams = 2200 g
So,
mass of Ba₃N₂ = 2200 g
Use the periodic table to determine the electron configuration for Ca and Pm in noble-gas notation
Ca:
Pm:
✓
Ca:
[Ar]4s
[Ar]4s
[Xe]6s2506
[Xe]6s25f4
Pm:
[Xe6s245
[Xe]6s244
[Ar]3s2
[kr]452
Answer:
Ca: [Ar] 4s²
Pm : [Xe} 6s² 4f⁵
Explanation:
The electronic configuation of an element in noble gas notation is written by giving the symbol of the nearest noble gas that is present in the period above it in the periodic table, followed by the electronic configuration of the remaining electrons.
For Ca the atomic no is 20
It is in 4th period.
The electronic configuration of Ca is 1s²2s²2p⁶3s²3p⁶4s²
1s²2s²2p⁶3s²3p⁶ represents the electronic congiguation of Ar with completely filled valence shell. So we can represent electronic configuration of Ca as [Ar] 4s².
The atomic no. of Promethium,Pm is 61. It's electronic configuration is
1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f⁵
1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶ is the configuration of the noble gas Xe . So we can represent electronic configuration of Pm as
[Xe} 6s² 4f⁵
Answer:
Ca: [Ar] 4s²
Pm : [Xe} 6s² 4f⁵
Explanation:
rank from the greatest to the least 1.43*10^6, 5.17*10^2, 2.34*10^5, 3.25*10^4, 4.56*10^3
Answer:
1.43×10⁶ > 2.34×10⁵> 3.25×10⁴>4.56×10³> 5.17×10²
Explanation:
First of all we will write these values in simple notation.
1) 1.43×10⁶
1.43×1000000
1430000
2) 5.17×10²
5.17×100
517
3) 2.34×10⁵
2.34×100000
234000
4) 3.25×10⁴
3.25×10000
32500
5) 4.56×10³
4.56×1000
4560
Rank from greatest to least.
1.43×10⁶ > 2.34×10⁵> 3.25×10⁴>4.56×10³> 5.17×10²
Jöns Jakob Berzellus _.
developed atomic theory
created the Periodic Table of Elements
proposed the planetary atomic model
Invented the chemical notation system
Answer:
Jöns Jakob Berzellus _
Invented the chemical notation system
Explanation:
Meaning of chemical notation : It is the representation of chemical composition of element by symbols.
Berzelius was the first person to measure accurate atomic weight of the elements, which helped to confirm Dalton's Atomic Theory.
He described how chemical bonds are formed by electrostatic attraction.
Berzelius, work with atomic weight and his theory of electrochemical dualism led to the development of Chemical notation that decide the chemical notation of the compounds.This chemical notation determines about the element both qualitatively and quantitatively.
He identified that compounds can be distinguished by the opposing constituents which are the acidic constituent , the basic and the neutral part.
This formula representation is given by Berzelius.
Answer:
Jöns Jakob Berzellus
Invented the chemical notation system
Explanation:
I got this one right on my test so it is right.
What are the 4 results of cell division?
Answer:
Metaphase
prophase
anaphase
telophase
Explanation:
What is true of greenhouse gases
Let us explain about green house gases
Explanation:
Green house effect
It can be explained as :
The sun emit radiations that consist of infra red rays , ultra violet rays and visible light .The infra red rays (responsible for heating ) when come from sun , it travels through atmosphere and reaches earth surface .On striking the earth surface , it gets reflected and reflected infra red ray has greater wavelength .Then this reflected rays moves back through atmosphere .On doing so , they encounter certain gas molecules like carbon dioxide , methane etc .This gases absorb these rays and do not let them to escape through them .As a result, they get trapped .As we have already mention that they cause heating effect , due to this property they raise the temperature of atmosphere leading global warming .Visible light that reaches the Earth from the Sun is known as white light. Which of the following statements about white light is true?
A.
White light is made up of only one color.
B.
White light falls within the microwave portion of the electromagnetic spectrum.
C.
White light is made up of a spectrum of many different colors.
D.
White light is made up mostly of ultraviolet and infrared light
PLEASEEEE PLEASEEE HELPPPPP
Answer:
C, hope this helps you!
The statement about white light which is true is: C. White light is made up of a spectrum of many different colors.
Light energy can be defined as an electromagnetic wave that does not require a medium of propagation, for it to travel through a vacuum (space), where no particles exist.
Also, light energy is mainly different from both sound and heat energy because light energy can exist independent of matter.
A white light can be defined as any form of visible light reaching planet Earth from the Sun. For example, the visible light energy from distant galaxy of stars and the Sun.
Generally, white light is a visible light that comprises a spectrum of several different colors such as red, orange, yellow, green, blue and violet.
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Identify the combustion reaction.
a) Al 2S 3 — 2A1 + 35
b) 2H 2 + O2 – 2H 20
c) C12 + 2KBr — 2KCI + Br2
d) C4H 12 + 70 2 - 6H 20 + 4CO 2
Answer:
D) C4H 12 + 70 2 - 6H 20 + 4CO 2
Explanation:
I'm certain this is a combustion reaction.
Which best explains why the game of economics does not have a single goal?
Most people do not know what economics is about.
• Some economic goals are not compatible with each other.
• Different people want different things out of life.
Economics is a game without winners or losers.
Answer: Different people want different things out of life
Your Welcome ^_^
What is the oh- given the value of h30+=(9.61x10^-2) M?
Answer:
OH⁻ = 1.05×10⁻¹³ M
Explanation:
Given data;
H₃O⁺ = 9.61×10⁻² M
OH⁻ = ?
Solution:
First of all we will calculate the pH.
pH = -log [H⁺]
pH = -log [H₃O⁺]
Because pH is also the hydronium ion concentration.
pH = -log [ 9.61×10⁻²]
pH = 1.02
It is known that,
pH + pOH = 14
1.02 + pOH = 14
pOH = 14 - 1.02
pOH = 12.98
Concentration of OH⁻.
pOH = -log [OH⁻]
12.98 = -log [OH⁻]
OH⁻ = 10∧-12.98
OH⁻ = 1.05×10⁻¹³ M
( Balance each equation) Na + MgF2 NaF + Mg
Answer:
2Na + MgF₂ → 2NaF + Mg
Explanation:
Chemical equation:
Na + MgF₂ → NaF + Mg
Chemical equation:
2Na + MgF₂ → 2NaF + Mg
The given reaction follow the law of conservation of mass because there are equal number of atoms of sodium, magnesium and fluorine are present on both side of equation.
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Type of reaction:
The given chemical reaction is type of single replacement reaction. Sodium replace the magnesium and form sodium fluoride.
Single replacement:
It is the reaction in which one elements replace the other element in compound.
AB + C → AC + B
If an atom gains an electron, what overall charge will it have?
Answer:
The atom will have a negative charge.
Explanation:
Electrons are subatomic particles with a negative charge, protons are subatomic particles with a negative charge, and neutrons have no charge. When a neutral atom's balance is disrupted by an extra electron, the atom becomes negatively charged.
Answer:
it will have a negative charge
Explanation:
which noble gas has the highest first ionization energy
Answer:
Helium has the highest First Ionization Energy in the Noble Gases group. Ionisation energy is the energy required to remove one mole of electrons from one mole of gaseous atoms.
Final answer:
Helium (He) has the highest first ionization energy among the noble gases, attributed to its stable valence shell configuration and minimal electron shielding effect.
Explanation:
The noble gas with the highest first ionization energy is Helium (He). This can be understood considering the general trend that ionization energy increases as one moves across a period from left to right in the periodic table. Noble gases, situated at the far right of the periodic table, consequently have the highest ionization energies within their respective periods due to their stable electronic configurations, with filled valence shells.
Among the noble gases, Helium, being the lightest and having the least number of electron shells, demonstrates the least shielding effect. This results in its valence electrons being more strongly attracted to the nucleus compared to other noble gases, thereby requiring more energy to remove an electron, i.e., higher ionization energy. In contrast, heavier noble gases like Xenon (Xe) and Radon (Rn) exhibit relatively lower first ionization energies due to increased electron shielding from inner electrons.
According to the periodic table, how many elements are a liquid at room tempreture
Give an example of a solution that can be seperated by simple distilation.
Answer: Evaporation of salt water
Explanation: During the process of evaporating salt water which involves simple distillation, pure water is separated with salt molecules.
When heated water evaporates from the solution since it is less dense. When condensed it becomes pure water and salt is left out since it is more denser.
What is the velocity of a rocket that goes 700 km north in 25 second
Answer: 28000m/s
Explanation:
Displacement = 700 km due north = 700000m
Time = 25secs
Velocity =?
Velocity = Displacement / Time
V = 700000 / 25 = 28000m/s
What best describes the goals of scientific investigation and technological development?
Both scientific investigation and technological design aim to solve problems by making more cost
products.
Both scientific investigation and technological design aim to conduct experiments to uncover new i
results.
Scientific investigation aims to design products that can make use of new information, whereas tec
aims to conduct experiments to improve affordability and availability.
Scientific investigation aims to design and implement an experiment to learn new information, where
development aims to design a product to solve a problem.
Answer:
Scientific investigation aims to design and implement an experiment to learn new information, where
development aims to design a product to solve a problem.
Explanation:
Answer:
D
Explanation:
Scientific investigation aims to design and implement an experiment to learn new information, whereas technological development aims to design a product to solve a problem.
Acceleration usually has the symbol a. It is a vector. What is the correct way
to write the symbol to show that it is a vector?
A. â
B. a
C. a
D. ā
Answer: D
The correct way of writing a vector is to put a bar (-) on it.
Acceleration usually has the symbol a. It is a vector. The correct way
to write the symbol to show that it is a vector is â. Option A is correct.
Acceleration refer to the rate of change of velocity with time. That is velocity divided by time.
Uniformly accelerated motion refer to the movement of velocity in a straight line and when the amount increase in velocity is in equal interval with amount increase in time.
Vector quantity is the quantity that have both magnitude and direction. Example include acceleration.
Scalar quantity refer to quantity with magnitude and no direction.
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Chemistry
How many water molecules are in 1.9 moles of water?
Use 6.022 X 1023 for Avogadro's Number!
Use "e-notation" when answering. 6.022 X 1023 would be entered as 6.022e23
Answer:
11.442E23molecules
Explanation:
Given data:
Number of moles of water = 1.9 mol
Number of molecules of water = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
In 1.9 moles:
1.9 mol × 6.022 × 10²³ molecules / 1 mol
11.442 × 10²³ molecules
In e notation:
11.442E23 molecules
The molecular weight of calcium carbonate, CaCO3, is 100.09 3.
mol
How many moles of calcium carbonate are in 63.8 g of calcium carbonate?
Express the answer using 3 significant figures.
Answer:
Number of Moles = Reacting mass / Molecular mass
= 63.8 / 100.09
= 0.637g
Hence, the moles of calcium carbonate in 63.8 g of calcium carbonate is 0.637g
Explanation:
The number of moles of a compound is the ratio of weight given to the molar mass. One mole calcium carbonate is 100.09 g/mol. Then, the number of moles in 63.8 g of calcium carbonate is 0.638 moles.
What is one mole of a substance ?One mole of a substance is its amount containing 6.02 × 10²³ number of its atoms. This number is called Avogadro number. Hence, one mole of any element contains Avogadro number of atoms. The mass of one mole of an element is called atomic mass.
Similarly one mole of any compound contains Avogadro number of molecules. The mass of one mole of the compound is called its molar mass.
Molar mass of calcium carbonate = 100.9 g/mol
given mass = 63.8 g
then, number of moles = 63.8 /100.9 g = 0.693 moles.
Therefore, the number of moles of 63.8 g of calcium carbonate is 0.693 moles.
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A metal cylinder is placed in a graduated cylinder which has been filled with water to the 70.0 mL mark. The water level rises to the 78.0 mL mark. What is the volume of the metal cylinder?
Answer:
Explanation V= New mL displaced water - original old water that was already in the grad. cylinder basically 8.0 mL:
The volume of the metal cylinder is found by calculating the difference between the initial and final water levels in a graduated cylinder, which is 8.0 mL in this instance.
Explanation:The volume of the metal cylinder can be determined using the water displacement method, where the initial volume of water in the graduated cylinder is recorded, and then the volume after placing the metal cylinder inside is measured. The difference between these two readings gives the volume of the metal cylinder. In this case, the initial volume is 70.0 mL, and after the cylinder is placed, the new volume is 78.0 mL.
The rise in water level, from 70.0 mL to 78.0 mL, indicates that the volume of the metal cylinder is 8.0 mL, since the volume of water displaced is equal to the volume of the submerged part of the cylinder.
It's important to consider factors such as the meniscus and potential distortions of the graduated cylinder's calibration when estimating and reading the volumes to ensure accuracy.
how manymoles are in 7.6g of ca
Answer: 0.19mol
Explanation
Mass of Ca = 7.6g
Molar Mass of Ca = 40g/mol
n = Mass /Molar Mass = 7.6/40
n = 0.19mol
6.755 mol Pb(SO4)2
How many atoms
Answer: 4.07x 10²⁴ atoms Pb( SO4)2
Explanation: Solution:
6.755 moles Pb(SO4)2 x 6.022x10²³ atoms Pb(SO4)2 / 1 mole Pb(SO4)2
= 4.07x10²⁴ atoms Pb(SO4)2